After a hiatus, “Forbidden Broadway” is back with sendups of “End of the Rainbow” (Jenny Lee Stern, left) and “Evita” (Natalie Charlé Ellis).Carol Rosegg

Broadway’s long sigh of relief is over: Gerard Alessandrini’s skewer-fest, “Forbidden Broadway,” is back with “Alive & Kicking!” Opening Sept. 6, it once again makes comic mincemeat of the Great White Way, after a three-year hiatus.

“The show went away because we ran out of stuff to talk about,” says Phillip George, Alessandrini’s longtime collaborator and co-director. “We decided to stop around the time they last revived ‘Guys and Dolls.’ Gerard just said, ‘What am I going to say? I’ve said it to death.’ He thought the time had come for him to take a breather and let Broadway change substantially enough that we could talk about something else.”

And so, after taking on the British invasion, the Disneyfication of Broadway and the rise of the meta-musicals, that time is now.

“The target we most wanted to hit was ‘Once,’ ” George says. The show lampoons the whimsical Tony winner in a song with the line “We’re so unpretentious that we’re pretentious!”

“It had been done to death on television,” George explains. “We were desperately trying to find something fresh to say about it until Julie Taymor told us to make it about the lawsuit between her and Bono. So we did what she said.”

It’s not the first time “Forbidden Broadway” subjects have happily lent a hand. Stephen Sondheim, a fan, frequently offers advice.

“He always says, ‘Not mean enough,’ ” George says. “Every time he comes to see the show, he talks to us afterwards. He’ll look at Gerard’s internal rhymes and tell him to sharpen them up. And years ago, when Carol Channing first came to see the show and she wasn’t in it, she called Gerard and demanded to know why not.”

On the other hand, Liza Minnelli was so afraid of how she’d be portrayed that she’s kept her distance.

And if Matthew Broderick knows what’s good for him, he’ll stay away, too. Marcus Stevens, who, like the rest of the ensemble, is new to “Forbidden Broadway,” plays the “Nice Work If You Can Get It” star in a fat-suit tuxedo.

Then again, costumes have always been a major part of the show, and for years, Alvin Colt — on a shoestring budget — rose to the challenge. Since Colt’s death four years ago, at age 91, Philip Heckman’s taken over.

“He’s a legend,” Heckman sighs. “They’re very big shoes to fill.” The first thing he did was visit the Brooklyn warehouse where all the past costumes are stored.

He says there are two kinds of costumes in “Forbidden Broadway” — ones that try to replicate the original, and the parody versions, like the classic “Lion King” outfit, replete with chopstick fingernails and a collar of torn-up plastic bags.

One new costume Heckman’s proud of is the two-piece suit worn in the “End of the Rainbow” sketch — a beaded, $3,500 duplicate of the one Judy Garland was to wear when she was slated for the lead in “Valley of the Dolls.” (“She did screen tests in her costumes, and stole all of them,” Heckman says. “And then she used them as her performance wardrobe.”)

The costume changes are fast and furious, and even with lots of Velcro and snaps, things don’t always go smoothly. At a recent preview, Jenny Lee Stern — segueing from “The Lion King” sketch to the “Jersey Boys” parody — nearly went onstage without her pants.

Meanwhile, the “Forbidden Broadway” team is already dreaming of future shtick.

“We’re looking forward to the Roundabout season,” George says, happily. “We’re toying around with a number where we spin a roulette wheel to choose the stars. Because they always seem like they’re throwing classics and stars at the wall to see if they stick.”